CampusModel.js

class Campus extends Sequelize.Model {}
Campus.init({
    name:{
        type:Sequelize.STRING,
        allowNull: false,
        notEmpty: true

    },
    imageUrl:{
        type:Sequelize.STRING,
        defaultValue: "https://hunter.cuny.edu",
    },
    address:{
        type:Sequelize.STRING,
        allowNull: false,
        notEmpty: true
    },
    description:{
        type:Sequelize.STRING,
        args:[0,500]
    },

},{
    sequelize,
    modelName:"campus"
})
Campus.associate = (models) => {
    Campus.hasMany(models.Students, {foreignKey: 'studentId'})
}

StudentsModel.js

class Students extends Sequelize.Model {}

    Students.init({
        firstName:{
            type:Sequelize.STRING,
            allowNull: false,
            notEmpty: true

        },
        lastName:{
            type:Sequelize.STRING,
            allowNull: false,
            notEmpty: true
        },
        email:{
            type:Sequelize.STRING,
            allowNull: false,
            notEmpty: true,
            isEmail: true
        },
        imageUrl:{
            type:Sequelize.STRING,
            defaultValue: "https://hunter.cuny.edu",
        },
        gpa:{
            type:Sequelize.DOUBLE,
            len: [0.0,4.0]
        },
        belongsTo:{
            type:Sequelize.STRING,
            notEmpty: true
        }
    },{
        sequelize,
        modelName:"students"
    });

    Students.associate = (models) => {
        Students.belongsTo(models.Campus, {foreignKey: 'campusId'})
    }